Re: Thorns on Aroids

These Silk Cotton trees may be exibiting a condition (whose name I can not recall at this moment!) where some species of tree exude ''something'' which prevents to growth of competing vines, etc. Here in Florida nothing will grow under the branches/drip- line OR climb a Norfolk Pine, and I believe Australian ''pines'' and even native Floridan pines demonstrate this "ability"!Perhaps someone ''out there'' has additional information on this one?

Leland, I wonder if there's a chemical that the Ceiba thorns exude that make it inhospitable to plants - it's not just Aroids that won't grow on them when they've got the thorns, they're completely free of competing species. Not even moss or lichen will grow on that bark! It's not particularly delicate or easy-sloughing either, just very very smooth over the thorn surface. Here at least, the thorns comprise the entire bark surface for the first 100 years or so of the tree's life. After that, it becomes a veritable epiphyte condominium, although the tree continues to produce some substance that inhibits the growth of strangler figs. I'd be interested to find out, but I have no clue how to go about testing for an unknown tree phytotoxin. It's not obvious, the way that it is for walnuts - although oddly enough, a slightly thorny Anthurium does tend to colonize these with no ill effects, even though the walnuts are suppressing all other plant growth in the area. I'm at a loss to explain that one.